Usually they don't differ too much. Matrix and talent 100 are said to be the most accurate, usually predicting atars within a 0.2 range
However the matrix calculator is now using the data from 2017 which might be inaccurate because 2017 was a really smart year, resulting in atars being dragged down more than expected. If our year is normal like the other years before 2017, the talent 100 calculator should be an accurate representation